Method, computer program, and devices for image acquisition

ABSTRACT

There is provided an image acquisition controller for acquiring an adapted image. The image acquisition controller comprises an interface towards a first image sensor, the first image sensor being arranged to acquire an image, and an interface towards a gaze tracking unit, the gaze tracking unit comprising a second image sensor for registering a gaze position on a scene associated with the image acquired by the first image sensor. The image acquisition controller is arranged to periodically receive information over the interface towards the gaze tracking unit about at least a position on the scene associated with the image provided from the first image sensor where the scene represents a larger part of an image registered by the first image sensor than intended to be acquired as the adapted image. The image acquisition controller is arranged to provide information over the interface towards the first image sensor about a position on the first image sensor, a size of a sensor area associated with the position on the first image sensor and a frame rate for image acquisition within said area. The image acquisition controller is arranged to receive image data over the interface towards the first image sensor wherein the image data at least comprises image data with the size, the position on the first image sensor, and the frame rate for image acquisition within said area such that the received image data is stored. An image acquisition system or device comprising the controller, a communication device with corresponding image acquisition capabilities, a method of image acquisition, and a computer program for implementing the method are also disclosed.

TECHNICAL FIELD

The present invention generally relates to an image acquisitioncontroller, an image acquisition system or device comprising thecontroller, a communication device with corresponding image acquisitioncapabilities, a method of image acquisition, and a computer program forimplementing the method. In particular, the invention relates toacquiring images in a power lean way.

BACKGROUND

In some digital camera applications, objects present in an image are tobe identified. Based on the identified objects, different functions maybe controlled, such as tracking the objects for focusing, recognisingthe objects for image classification, suggested cropping of the image,etc. One approach for identifying these objects are to use imageprocessing algorithms such as Speeded-Up Robust Features (SURF), ScaleInvariant Feature Transform (SIFT), Oriented FAST and Rotated BRIEF(ORB), where FAST is corner detection method Features from AcceleratedSegment Test and BRIEF is visual descriptor Binary Robust IndependentElementary Features, etc. One issue with such image processingalgorithms is that they are consuming considerable computing and powerresources, especially when applied to large image data. This may bealleviated by performing the processing at a host which is lessconstrained in those senses than for example a portable device capturingthe image. However, there is still a drawback when the transmission ofthe large image data is to be provided to the host, e.g. over a wirelessinterface.

It is therefore a desire to limit the amount of data to be processedand/or to be transmitted for processing at a host. However, this createsa Catch-22 problem since the selection of objects to limit the amount ofdata to be processed is what the limitation is for. It is thus a problemhow to tie up this Catch-22 problem.

The above information disclosed in this Background section is only forenhancement of understanding of the background of the invention andtherefore it may contain information that does not form the prior artthat is already known to a person of ordinary skill in the art.

SUMMARY

The invention is based on the understanding that at image capturing by aperson, where the person uses a view, such as for augmented realityapplications, or preview such as a screen or a viewfinder, the person'seye will inherently look at the points of interest in the scene wherethe objects are likely to be found. The inventors have realized that bymaking a pre-selection based on the person's gaze, using eye tracking,the parts of the originally captured image by an image sensor can beselected and stored. The stored adapted, i.e. limited, image can then beprocessed or transmitted for processing at a host.

According to a first aspect, there is provided an image acquisitioncontroller for acquiring an adapted image. The image acquisitioncontroller comprises an interface towards a first image sensor, thefirst image sensor being arranged to acquire an image, and an interfacetowards a gaze tracking unit, the gaze tracking unit comprising a secondimage sensor for registering a gaze position on a scene associated withthe image acquired by the first image sensor. The image acquisitioncontroller is arranged to periodically receive information over theinterface towards the gaze tracking unit about at least a position onthe scene associated with the image provided from the first image sensorwhere the scene represents a larger part of an image registered by thefirst image sensor than intended to be acquired as the adapted image.The image acquisition controller is arranged to provide information overthe interface towards the first image sensor about a position on thefirst image sensor, a size of a sensor area associated with the positionon the first image sensor and a frame rate for image acquisition withinsaid area. The image acquisition controller is arranged to receive imagedata over the interface towards the first image sensor wherein the imagedata at least comprises image data with the size, the position on thefirst image sensor, and the frame rate for image acquisition within saidarea such that the received image data is stored.

The image acquisition may be arranged to monitor timing of theinformation over the interface towards the gaze tracking unit about agaze at the respective position on the scene, wherein the size of thesensor area associated with the position depends on a duration of thegaze at the position, respectively.

The interface towards the first image sensor may comprise a controlinterface arranged to provide the information about the position on thefirst image sensor, the size of a sensor area associated with theposition on the first image sensor and the frame rate for imageacquisition within said area, and an image data interface arranged toreceive the image data.

At least one of the size of the sensor area associated with the positionon the first image sensor and the frame rate for image acquisitionwithin the area may depend on a number of periodically receivedpositions being within a distance from each other below a firstthreshold.

The size of the sensor area associated with the position on the firstimage sensor may be arranged to increase with a number of periodicallyreceived positions being within a distance from each other above a firstthreshold and below a second threshold, wherein the increased sensorarea grows in a direction of movement of positions of the periodicallyreceived positions.

The image acquisition controller may be arranged to recognise objectsfrom the image data, wherein the information about the position on thefirst image sensor and the size of the sensor area associated with theposition on the first image sensor provided over the interface towardsthe first image sensor is adapted based on a found object.

According to a second aspect, there is provided an image acquisitionsystem comprising a first image sensor arranged to acquire an image, agaze tracking unit comprising a second image sensor for registering agaze position on a scene associated with the image acquired by the firstimage sensor, and an image acquisition controller according to the firstaspect.

According to a third aspect, there is provided a communication devicecomprising a transceiver arranged to communicate with a communicationsnetwork, and an image acquisition system according to the second aspect,wherein the communication device is capable of transmitting an adaptedimage based on the stored image data via the transceiver.

According to a fourth aspect, there is provided an image acquisitionmethod comprising acquiring an image by a first image sensor,registering a series of gaze positions at a scene associated with theimage acquired by the first image sensor, providing information to thefirst image sensor about a position on the first image sensor, a size ofa sensor area associated with the position on the first image sensor anda frame rate for image acquisition within said area, receiving imagedata from the first image sensor wherein the image data at leastcomprises image data with the size, the position on the first imagesensor, and the frame rate for image acquisition within said area, andstoring an adapted image based on the received image data, where thescene represents a larger part of an image registered by the first imagesensor than intended to be acquired as the adapted image.

The method may comprise monitoring timing of the gaze at the respectiveposition on the scene, wherein the size of the sensor area associatedwith the position depends on a duration of the gaze at the position,respectively.

At least one of the size of the sensor area associated with the positionon the first image sensor and the frame rate for image acquisitionwithin the area may depend on a number of periodically receivedpositions being within a distance from each other below a firstthreshold.

The size of the sensor area associated with the position on the firstimage sensor may be arranged to increase with a number of periodicallyreceived positions being within a distance from each other above a firstthreshold and below a second threshold, wherein the increased sensorarea grows in a direction of movement of positions of the periodicallyreceived positions.

The method may comprise recognising objects from the image data, whereinthe information about the position on the first image sensor and thesize of the sensor area associated with the position on the first imagesensor provided over the interface towards the first image sensor isadapted based on a found object.

According to a fourth aspect, there is provided a computer programcomprising instructions which, when executed on a processor of an imageacquisition device, causes the image acquisition device to perform themethod according to the fourth aspect. A scene in this context is a partof reality that is enabled to be captured by one or more image sensorsof one or more cameras of an available image acquisition system. Thegaze tracking unit is thus enabled to register what piece or part ofthat scene that a user is looking at, which may be looked at directly,through a viewfinder, on a preview screen, etc.

BRIEF DESCRIPTION OF THE DRAWINGS

The above, as well as additional objects, features and advantages of thepresent invention, will be better understood through the followingillustrative and non-limiting detailed description of preferredembodiments of the present invention, with reference to the appendeddrawings.

FIG. 1 schematically illustrates elements of an image acquisition deviceaccording to an embodiment.

FIG. 2 is a flow chart illustrating a method according to an embodiment.

FIG. 3 illustrates a scene used for explaining principles of someembodiments.

FIG. 4 illustrates the scene of FIG. 3 where gaze tracking has pickedareas to analyse.

FIG. 5 illustrates cropped images from the scene of FIG. 3 using thegaze tracking information indicated in FIG. 4.

FIG. 6 is a flow chart illustrating a method according to an embodiment.

FIG. 7 is a block diagram schematically illustrating a communicationdevice comprising an image acquisition device according to anembodiment.

FIG. 8 schematically illustrates a computer-readable medium and aprocessing device.

DETAILED DESCRIPTION

Digital cameras, comprised in various devices, may be used for streamingcontent with object recognition, wherein full frames or lower resolutionwith full field of view of the camera may be used. This is done so thatall objects that the camera can detect should be detected. For findingobjects in an image, different algorithms can be used such as SURF,SIFT, ORB etc. These algorithms are specialized in finding edges,transitions etc. to point out where objects of interest might be. Oncean object is detected the image can be cropped to a suitable size andprocessed in an image recognition algorithm. The herein suggestedapproach to tie up the Catch-22 case discussed above is to let thecamera work more like the human eye. The field of view of the eye thatproduces a sharp image in colour is only a few degrees (Area of cones inthe eye). The brain puts an image together based on the movement of theeye, which makes an image that is perceived larger than the narrow fieldof view of the cones. The eye will thus scan the parts of the scenecomprising anything catching the interest of a person looking at thescene, e.g. on a preview screen or in a viewfinder, or in actual realitybeing imaged such as for augmented reality applications. For example,the preview image is captured at a lower resolution but over the wholeimage sensor area, which is enough for providing a preview on a screenfor the user. The identified points of interest, made by tracking theeye of the user, may on the other hand be captured with higherresolution, i.e. an area around the identified points of interest, andthe size of respective area may be determined from the tracking of theeye, e.g. from the time it is looked at, movements around the point ofinterest, etc.

Eye tracking, or gaze tracking, is known. A suitable approach is opticaltracking which uses some non-contact, optical method for measuring eyemotion. Light, typically infrared, may be reflected from the eye andsensed by a video camera or some other specially designed opticalsensor. The information is then analysed to extract eye rotation fromchanges in reflections. Video-based eye trackers typically use thecorneal reflection and the centre of the pupil as features to track overtime. A more sensitive type of eye-tracker uses reflections from thefront of the cornea and the back of the lens as features to track. Astill more sensitive method of tracking is to image features from insidethe eye, such as the retinal blood vessels, and follow these features asthe eye rotates. Optical methods, particularly those based on videorecording, are widely used for gaze tracking and are favoured for beingnon-invasive and inexpensive.

FIG. 1 schematically illustrates elements involved in the suggestedapproach. An image acquisition controller 100 is arranged to host a gazeposition algorithm 102, a camera control algorithm 104, and optionallyan image recognition algorithm 105. The gaze position algorithm 102interfaces with an eye tracking unit 106, which typically comprises animage sensor arranged to capture images of the user's eye. Other meansfor eye tracking is of course possible, but the approach to use an imagesensor for tracking the eye have the benefit of not being intrusive onthe user's body and provides a good accuracy. The camera controlalgorithm 104 interfaces with one or more cameras 108, i.e. imagesensors which are controllable in sense of e.g. size, resolution, framerate, etc. The image acquisition controller 100 may also interface witha memory 107 for storage of acquired images. The image acquisitioncontroller 100 may also interface with an inertial measurement unit,IMU, 109, a global navigation satellite system, GNSS, receiver 111, orother sensors or information acquisition means 113 for furtherfunctionality of the image acquisition, e.g. for augmented reality, AR,applications.

The eye tracking unit 106 will output a signal holding information aboutthe user's eye position and direction. The gaze position algorithm 102will from this signal determine a corresponding position in relation toan image sensor of the one or more cameras 108, respectively.

The interface between the camera control algorithm 104 and the one ormore image sensors of the camera(s) 108 typically comprises one controlinterface where the camera control algorithm provides controlinformation about e.g. position, size, resolution, frame rate, etc. tomake the sensor acquire the desired image data, which may be transmittedto the image acquisition controller 100 over a second interface, or overa common interface for the control information and image data. Thecontrol information provided to the image sensor is based on the outputfrom the gaze position algorithm 102. For example, the gaze positionalgorithm determines that the user's eye is directed towards positionsin vicinity of each other during some time, wherein the positionprovided to the image sensor is a mean position of those positions, andthe size of a cropped part of the entire image sensor area to beacquired, and possibly the desired resolution thereof, provided to theimage sensor depends e.g. on the time the user gazed at that area, andpossibly on the spread of the determined positions, assuming that anobject with a certain size was observed, may determine the size of thecropping, and possibly also the resolution. For example, a small spreadof the determined positions may indicate a small object, and thereforemaybe a high resolution is desired. A larger spread may indicate alarger object, and to keep amount of information within some bounds theresolution may be reduced while a larger size cropping is selected. Forsome applications, the resolution may be kept constant, and for someother applications, the size may be kept constant.

The acquired cropped image or images may be stored in the memory 107,from where it can be accessed and for example be further processed, e.g.for object recognition.

The image acquisition controller 100 periodically receives informationover the interface towards the gaze tracking unit 106 about at least aposition on the scene provided from the image sensor(s) 108 where thescene represents a larger part of an image registered by the first imagesensor than intended cropped image to be acquired as the adapted image.The image acquisition controller 100 may thus monitor timing of theinformation over the interface towards the gaze tracking unit 106 abouta gaze at the respective position on the scene, wherein the size of thesensor area associated with the position depends on a duration of thegaze at the position, respectively. The interface between the imageacquisition controller 100 and the image sensor(s) may include a controlinterface arranged to provide the information about the position on thefirst image sensor, the size of a sensor area associated with theposition on the first image sensor and the frame rate for imageacquisition within said area, and an image data interface arranged toreceive the image data. For example, at least one of the size of thesensor area associated with the position on the first image sensor andthe frame rate for image acquisition within the area may depend on anumber of periodically received positions being within a distance fromeach other below a first threshold, or the size of the sensor areaassociated with the position on the first image sensor may be arrangedto increase with a number of periodically received positions beingwithin a distance from each other above a first threshold and below asecond threshold, where the size of the cropped sensor area grows in adirection of movement of positions of the periodically receivedpositions.

The approach provides the advantage that objects of interest may befound easier with less consumption of computing effort and powerconsumption. However, the traditional object identification can still beapplied but within the cropped images. The object identification dataretrieved thereby can then be used in an iterative way to further refinecropping of images. The image acquisition controller can for examplerecognise objects from the adapted image data, wherein the informationabout the position on the first image sensor and the size of the sensorarea associated with the position on the image sensor provided over theinterface towards the first image sensor is adapted based on a foundobject to retrieve a further refined cropping, e.g. with a higherresolution and/or for extracting desired parts to be conveyed forfurther processing, locally or at a remote host. Here, the refinedcropping can also comprise enlarging the cropped area.

The image acquisition controller 100 may be used in different kind ofdevices, such as digital cameras, gaming devices, etc. Any such devicecan be considered as an image acquisition system comprising at least afirst image sensor 108 arranged to acquire an image, a gaze trackingunit 106 comprising a second image sensor for registering a gazeposition on a scene associated with an image acquired by the first imagesensor, and an image acquisition controller 100 as demonstrated above.The image acquisition system can also be part of a general-purposecommunication device such as a smartphone. The communication device canthus comprise a transceiver arranged to communicate with acommunications network, and the image acquisition system. Thecommunication device can for example transmit an adapted image based onone or more stored images, i.e. cropped identified parts from the imagesensor, via the transceiver. One application for the image acquisitioncontroller 100 is for controlling augmented reality, AR, applications,where the image acquisition system includes, in addition to the imageacquisition controller 100, a processing device for providing anenhanced image and a display, preferably adapted for the AR application,to provide the image enhancements. This would provide for an AR device.Other applications, such as virtual reality, VR, applications, enhanceduser interfaces, UIs, including for example AR features, tactileenhancements, etc., gaming applications, etc., and corresponding deviceswould be readily derivable from this disclosure.

FIG. 2 is a flow chart illustrating an image acquisition methodaccording to embodiments. The method comprises acquiring 200 an image bya first image sensor, i.e. the one of the actual camera, and registering202 a series of gaze positions at a scene associated with the imageacquired by the first image sensor, providing 204 information to thefirst image sensor about a position, corresponding to the registeredposition, on the first image sensor, a size of a sensor area associatedwith the position on the first image sensor and a frame rate for imageacquisition within said area, receiving 206 image data from the firstimage sensor wherein the image data at least comprises image data withthe size of activated part of the first image sensor, the position onthe first image sensor, and the frame rate for image acquisition withinsaid area, and storing 208 an adapted image based on the received imagedata. The scene represents a larger part of an image registered by thefirst image sensor than intended to be acquired as the adapted image.

The size of the sensor area associated with the respective position canfor example depend on a duration of the gaze at the position. This canbe achieved by monitoring 203 timing of the gaze at the respectiveposition on the image.

The providing 204 of the information about the position on the firstimage sensor, the size of a sensor area associated with the position onthe first image sensor and the frame rate for image acquisition withinsaid area to the first image sensor causes the image sensor to provideimage data accordingly such that the image data related to the providedinformation can be received 206 from the first image sensor. Theselection of parameters such as size, frame rate, etc. for respectiveidentified position may be determined from the gaze information based onsome assumptions. For example, at least one of the size of the sensorarea associated with the position on the first image sensor and theframe rate for image acquisition within the area may depend on severalperiodically received positions being within a distance from each otherbelow a first threshold. Here, the assumption may be made that the userlooks at an object for a while wherein the parameters are selected suchthat image(s) is(are) retrieved with desired quality and covering theobject. Another example may be that the size of the sensor areaassociated with the position on the first image sensor is arranged toincrease with several periodically received positions being within adistance from each other above a first threshold and below a secondthreshold, wherein the increased sensor area grows in a direction ofmovement of positions of the periodically received positions. Here, theassumption may be that an observed object has a certain size on theimage sensor and that the gaze sweeps over the size of the object.

As discussed above, object recognition may be iterative in sense that afirst iteration comprises the gaze-controlled cropping and a seconditeration comprises object recognition by signal processing based on thefirst cropping. The method may thus comprise recognising 207 objectsfrom the image data, wherein the information about the position on thefirst image sensor and the size of the sensor area associated with theposition on the first image sensor provided over the interface towardsthe first image sensor is adapted based on a found object, and anotherretrieval of image data is performed to get to the adapted image to bestored 208. One example is that the image recognition in this iterationis a crude image processing made locally to get a fair enoughidentification to improve the cropping, while the stored image then maybe more seriously processed, e.g. at a remote unit having betterprocessing capabilities in sense of processing power and/or availableenergy, to make a final object recognition.

FIG. 3 represents a scene enabled to be captured as an image, asdiscussed above. FIG. 4 represents the same scene where results of gazetracking is indicated. The curved arrow here represents the general eyemovement and the squares indicate periodically determined positions.Thus, along some parts of the curved arrow, the eye movement has beentoo quick to set off a square, which is assumed to mean that the userdid not find anything interesting there. At some parts, multipleoverlapping squares have been set off, assumed to indicate points ofinterest. Based on the tracked gaze, parameters are assumed to be formedand provided to the image sensor which then has provided croppedsub-images, as indicated in FIG. 5, to be stored.

FIG. 6 is a flow chart illustrating a method according to an embodiment.Eye position is tracked 600. From the eye tracking information, a gazeposition is calculated 601 which corresponds to a position on an imagesensor arranged to capture the desired image. Timing of gazing ismonitored by updating 602 a gaze position timer. Thereby, it can bemonitored whether the user gazes at a certain part corresponding to apart of the scene which may be assumed to hold an object of interest. Anobject is here something which will be imaged by the image sensor. Basedon the calculated position(s) and the timing thereof, parameters for thecamera with its image sensor are updated 603, and the camera outputs 604image(s) based on the parameters. It is determined 605 whether the gazeposition timer for a gaze position, where positions in close vicinity,e.g. having a mutual distance below a threshold, are counted as oneposition for the determination, is below a time threshold. If the timeris below the time threshold, the procedure 600-604 is repeated. If thetimer has reached the time threshold, object recognition for theposition is performed 606. That is, image data in an area around theposition is processed to recognize an object, e.g. using any of theimage recognition algorithms discussed above. It is determined 607whether an object was found. If no object was found, the procedurereturns to tracking 600 the eye position. If an object was found, cameraparameters are updated 608 accordingly. That is, the camera isinstructed to capture an image corresponding to the found object. Thegaze tracking algorithm may also be updated 609 based on the successfulcapturing of the object. The procedure then continues with the eyetracking 600.

FIG. 7 is a block diagram schematically illustrating an imageacquisition device 700 according to an embodiment. The image acquisitiondevice may be capable of wireless communication and then comprises anantenna arrangement 702, a receiver 704 connected to the antennaarrangement 702, and a transmitter 706 connected to the antennaarrangement 702. The image acquisition device comprises a processingelement 708 which may comprise one or more circuits, one or more inputinterfaces 710 and one or more output interfaces 712. The interfaces710, 712 can be user interfaces and/or signal interfaces, e.g.electrical or optical. The image acquisition device 700 may be arrangedto operate in a cellular communication network.

The image acquisition device 700 comprises circuitry 714 for gazecontrolled image acquisition, i.e. elements as demonstrated withreference to FIG. 1. The circuitry 714 for gaze controlled imageacquisition is connected to the processing element 708, which maycontribute with some or all of the control and/or processingdemonstrated above. In particular, by the processing element 708 beingarranged to support the performing of the embodiments demonstrated withreference to FIGS. 2 to 6, the image acquisition device 700 is capableof the power lean image acquisition as discussed above. The processingelement 708 can also fulfil a multitude of tasks, ranging from signalprocessing to enable reception and transmission since it is connected tothe receiver 704 and transmitter 706, executing applications,controlling the interfaces 710, 712, etc.

One advantage according to some embodiments is that only selected partsof the image sensor(s) which are of interest are activated, e.g. forhigh-resolution image registration, which is inherently power saving.

One advantage according to some embodiments is that only selected partsof the scene is subject for image capturing and saving, and possiblyprocessing, which is inherently power saving.

Further advantages, such as limitation of heat generation in imagesensor(s), limitation of use of bandwidth of busses and/or externalinterfaces, increased speed of processing for given hardware resources,etc. may also be provided.

The methods according to the present invention is suitable forimplementation with aid of processing means, such as computers and/orprocessors, especially for the case where the processing element 708demonstrated above comprises a processor controlling the power leanimage acquisition. Therefore, there is provided computer programs,comprising instructions arranged to cause the processing means,processor, or computer to perform the steps of any of the methodsaccording to any of the embodiments described with reference to FIG. 2to 6. The computer programs preferably comprise program code which isstored on a computer readable medium 800, as illustrated in FIG. 8,which can be loaded and executed by a processing means, processor, orcomputer 802 to cause it to perform the methods, respectively, accordingto embodiments of the present invention, preferably as any of theembodiments described with reference to FIGS. 2 to 6. The computer 802and computer program product 800 can be arranged to execute the programcode sequentially where actions of the any of the methods are performedstepwise, or perform actions on a real-time basis. The processing means,processor, or computer 802 is preferably what normally is referred to asan embedded system. Thus, the depicted computer readable medium 800 andcomputer 802 in FIG. 8 should be construed to be for illustrativepurposes only to provide understanding of the principle, and not to beconstrued as any direct illustration of the elements.

1. An image acquisition controller for acquiring an adapted image, theimage acquisition controller comprising: an interface towards a firstimage sensor, the first image sensor being arranged to acquire an image;and an interface towards a gaze tracking unit, the gaze tracking unitcomprising a second image sensor for registering a gaze position on ascene associated with an image acquired by the first image sensor,wherein the image acquisition controller is arranged to periodicallyreceive information over the interface towards the gaze tracking unitabout at least a position on the scene associated with the imageprovided from the first image sensor where the scene represents a largerpart of an image registered by the first image sensor than intended tobe acquired as the adapted image; the image acquisition controller isarranged to provide information over the interface towards the firstimage sensor about a position on the first image sensor, a size of asensor area associated with the position on the first image sensor and aframe rate for image acquisition within said area; and the imageacquisition controller is arranged to receive image data over theinterface towards the first image sensor wherein the image data at leastcomprises image data with the size, the position on the first imagesensor, and the frame rate for image acquisition within said area suchthat the received image data is stored.
 2. The image acquisitioncontroller of claim 1, wherein the image acquisition controller isarranged to monitor timing of the information over the interface towardsthe gaze tracking unit about a gaze at the respective position on thescene, wherein the size of the sensor area associated with the positiondepends on a duration of the gaze at the position, respectively.
 3. Theimage acquisition controller of claim 1 or 2, wherein the interfacetowards the first image sensor comprises: a control interface arrangedto provide the information about the position on the first image sensor,the size of a sensor area associated with the position on the firstimage sensor and the frame rate for image acquisition within said area;and an image data interface arranged to receive the image data.
 4. Theimage acquisition controller of claim 1, wherein at least one of thesize of the sensor area associated with the position on the first imagesensor and the frame rate for image acquisition within the area dependson a number of periodically received positions being within a distancefrom each other below a first threshold.
 5. The image acquisitioncontroller of claim 1, wherein the size of the sensor area associatedwith the position on the first image sensor is arranged to increase witha number of periodically received positions being within a distance fromeach other above a first threshold and below a second threshold, whereinthe increased sensor area grows in a direction of movement of positionsof the periodically received positions.
 6. The image acquisitioncontroller of claim 1, arranged to recognise objects from the imagedata, wherein the information about the position on the first imagesensor and the size of the sensor area associated with the position onthe first image sensor provided over the interface towards the firstimage sensor is adapted based on a found object.
 7. An image acquisitionsystem comprising: a first image sensor arranged to acquire an image; agaze tracking unit comprising a second image sensor for registering agaze position on a scene associated with an image acquired by the firstimage sensor; and an image acquisition controller according to claim 1.8. A communication device comprising: a transceiver arranged tocommunicate with a communications network; and an image acquisitionsystem according to claim 7, wherein the communication device is capableof transmitting an adapted image based on the stored image data via thetransceiver.
 9. An image acquisition method comprising: acquiring animage by a first image sensor; registering a series of gaze positions ata scene associated with the image acquired by the first image sensor;providing information to the first image sensor about a position on thefirst image sensor, a size of a sensor area associated with the positionon the first image sensor and a frame rate for image acquisition withinsaid area; receiving image data from the first image sensor wherein theimage data at least comprises image data with the size, the position onthe first image sensor, and the frame rate for image acquisition withinsaid area; and storing an adapted image based on the received imagedata, where the scene represents a larger part of an image registered bythe first image sensor than intended to be acquired as the adaptedimage.
 10. The method of claim 9, comprising monitoring timing of thegaze at the respective position on the scene, wherein the size of thesensor area associated with the position depends on a duration of thegaze at the position, respectively.
 11. The method of claim 9, whereinat least one of the size of the sensor area associated with the positionon the first image sensor and the frame rate for image acquisitionwithin the area depends on a number of periodically received positionsbeing within a distance from each other below a first threshold.
 12. Themethod of claim 9, wherein the size of the sensor area associated withthe position on the first image sensor is arranged to increase with anumber of periodically received positions being within a distance fromeach other above a first threshold and below a second threshold, whereinthe increased sensor area grows in a direction of movement of positionsof the periodically received positions.
 13. The method of claim 9,comprising recognising objects from the image data, wherein theinformation about the position on the first image sensor and the size ofthe sensor area associated with the position on the first image sensorprovided over the interface towards the first image sensor is adaptedbased on a found object.
 14. A non-transitory computer readable storagemedium comprising a computer program comprising instructions which, whenexecuted on a processor of an image acquisition device, causes the imageacquisition device to perform an image acquisition method comprising:acquiring an image by a first image sensor; registering a series of gazepositions at a scene associated with the image acquired by the firstimage sensor; providing information to the first image sensor about aposition on the first image sensor, a size of a sensor area associatedwith the position on the first image sensor and a frame rate for imageacquisition within said area; receiving image data from the first imagesensor wherein the image data at least comprises image data with thesize, the position on the first image sensor, and the frame rate forimage acquisition within said area; and storing an adapted image basedon the received image data, where the scene represents a larger part ofan image registered by the first image sensor than intended to beacquired as the adapted image.